Power control in telecommunications networks

Abstract

A radio frequency transmitter is power controlled using a controlling system including an integrating controller, together with an inner and an outer control loop. A tracking signal supplied by the inner loop to the integrating controller of the outer loop is used to avoid windup problems when the transmitted power is saturated.

1. A method for controlling a radio frequency (RF) transmitter, the method comprising:
 using an integrating controller to produce a reference value of a first quality measure from a first error signal wherein the first error signal is based on a reference value of a second quality measure and an estimated value of the second quality measure, wherein the integrating controller is one of a proportional integrating (PI) controller having the transfer function: 
 
     
       
         
           
             
               SIR 
               r 
             
             = 
             
               
                 
                   e 
                   * 
                 
                 ⁢ 
                 K 
               
               + 
               
                 
                   1 
                   s 
                 
                 ⁢ 
                 
                   ( 
                   
                     
                       
                         
                           e 
                           * 
                         
                         ⁢ 
                         K 
                       
                       
                         T 
                         i 
                       
                     
                     + 
                     
                       
                         e 
                         s 
                       
                       
                         T 
                         t 
                       
                     
                   
                   ) 
                 
               
             
           
         
       
       in which SIR r  is the reference value of the first quality measure, e is the error in quality measure, K is a constant, e s  is the tracking signal and T i  and T t  are time constants relating to the integration and tracking unit respectively, or a proportional integrating derivative (PID) controller; 
       producing an estimated value of the first quality measure relating to an actual value of the first quality measure; and 
       supplying a tracking signal related to the estimated value of the first quality measure and the reference value of a first quality measure to the integrating controller. 
     
   
   
     2. A method for controlling a radio frequency (RF) transmitter, the method comprising:
 using an integrating controller to produce a reference value of a first quality measure from a first error signal wherein the first error signal is based on a reference value of a second quality measure and an estimated value of the second quality measure; 
 producing an estimated value of the first quality measure relating to an actual value of the first quality measure; and 
 supplying a tracking signal related to the estimated value of the first quality measure and the reference value of a first quality measure to the integrating controller, wherein an adjusted tracking signal is set to zero when the tracking signal is within a predefined value range, the adjusted tracking signal being supplied to the integrating controller in place of the tracking signal. 
 
   
   
     3. A method as claimed in  claim 2 , wherein the adjusted tracking signal is set to zero if the absolute value of the tracking signal is less than a predetermined threshold value. 
   
   
     4. A method for controlling a radio frequency (RF) transmitter, the method comprising:
 using an integrating controller to produce a reference value of a first quality measure from a first error signal wherein the first error signal is based on a reference value of a second quality measure and an estimated value of the second quality 
 producing an estimated value of the first quality measure relating to an actual value of the first quality measure; and 
 supplying a tracking signal related to the estimated value of the first quality measure and the reference value of a first quality measure to the integrating controller, wherein the integrating controller is operable to not update the integrator if the tracking signal indicates that an update would not be advisable, and wherein the integrating controller is operable to not update the integrator if the tracking signal indicates that the absolute value of the difference between the estimated value of the first quality measure and the reference value of the first quality measure is larger than a threshold. 
 
   
   
     5. A controller for controlling a radio frequency (RF) transmitter, the method comprising:
 an integrating controller operable to produce a reference value of a first quality measure from a first error signal, wherein the first error signal is based on a reference value of a second quality measure and an estimated value of the second quality measure, wherein the integrating controller is one of a proportional integrating (PI) controller, having the transfer function: 
 
     
       
         
           
             
               SIR 
               r 
             
             = 
             
               
                 
                   e 
                   * 
                 
                 ⁢ 
                 K 
               
               + 
               
                 
                   1 
                   s 
                 
                 ⁢ 
                 
                   ( 
                   
                     
                       
                         
                           e 
                           * 
                         
                         ⁢ 
                         K 
                       
                       
                         T 
                         i 
                       
                     
                     + 
                     
                       
                         e 
                         s 
                       
                       
                         T 
                         t 
                       
                     
                   
                   ) 
                 
               
             
           
         
       
       in which SIR r  is the reference value of the first quality measure, e is the error in quality measure, K is a constant, e s  is the tracking signal and T i  and T t  are time constants relating to the integration and tracking unit respectively, or a proportional integrating derivative (PID) controller, 
       an estimator operable to produce an estimated value of the first quality measure relating to an actual value of the first quality measure; and 
       a tracking unit operable to supply a tracking signal related to the estimated value of the first quality measure and the reference value of a first quality measure to the integrating controller. 
     
   
   
     6. A controller for controlling a radio frequency (RF) transmitter, the method comprising:
 an integrating controller operable to produce a reference value of a first quality measure from a first error signal, wherein the first error signal is based on a reference value of a second quality measure and an estimated value of the second quality measure; 
 an estimator operable to produce an estimated value of the first quality measure relating to an actual value of the first quality measure; and 
 a tracking unit operable to supply a tracking signal related to the estimated value of the first quality measure and the reference value of a first quality measure to the integrating controller, wherein the tracking unit is operable to produce an adjusted tracking signal which is set to zero when the tracking signal is within a predefined value range, the adjusted tracking signal being applied in place of the tracking signal. 
 
   
   
     7. A controller for controlling a radio frequency (RF) transmitter, the method comprising:
 an integrating controller operable to produce a reference value of a first quality measure from a first error signal, wherein the first error signal is based on a reference value of a second quality measure and an estimated value of the second quality measure; 
 an estimator operable to produce an estimated value of the first quality measure relating to an actual value of the first quality measure; and 
 a tracking unit operable to supply a tracking signal related to the estimated value of the first quality measure and the reference value of a first quality measure to the integrating controller, wherein the integrating controller is operable to not update the integrator if the tracking signal indicates that an update would not be advisable and wherein the integrating controller is operable to not update the integrator of the tracking signal indicates that the absolute value of the difference between the estimated value of the first quality measure and the reference value of the first quality measure is larger than a threshold. 
 
   
   
     8. A method according to  claim 1 , as implemented in a computer program product comprising code elements adapted to be executed on a computer.